The invention relates to improvements in methods of and in apparatus for making rod-shaped smokers' products of the type wherein a tobacco-containing section is attached to one end of a filter material containing section by an adhesive-carrying uniting band. A large majority of such smokers' products constitute (and will hereinafter be referred to as) filter cigarettes.
Apparatus which are presently utilized for the mass production of filter cigarettes are known as filter tipping machines or filter assemblers. Well known types of such machines are MAX 70, MAX 90, MAX 100 and MAX-S filter assemblers which are produced and distributed by the assignee of the present application. Such machines are normally assembled with plain cigarette makers and filter rod makers into production lines (e.g., those known as PROTOS 2, PROTOS 70, PROTOS 90 and PROTOS 100, all produced and distributed by the assignee of the present application) which are capable of turning out huge quantities of filter cigarettes per unit of time.
A MAX filter assembler is designed to transport a continuous series of successive groups of coaxial plain cigarettes and filter rod sections sideways, i.e., transversely of the longitudinal axes of such groups. Each group can contain plain cigarettes of single or multiple (e.g., double) unit length and a corresponding number of filter rod sections of unit length or multiple unit length. It is presently preferred to assemble groups wherein a filter rod section of double unit length is flanked by two plain cigarettes of unit length. Successive groups of the series are provided with adhesive-carrying uniting bands made of so-called tipping paper, and the bands are convoluted around the filter rod sections of double unit length as well as around the adjacent portions of the plain cigarettes to convert each group into a filter cigarette of double unit length. Each such filter cigarette of double unit length is thereupon severed midway across its filter rod section of double unit length to yield a pair of filter cigarettes of unit length. The uniting bands are obtained by advancing a continuous web of tipping paper (e.g., imitation cork) from a bobbin, reel or another suitable source, first past an adhesive applying station and thereupon past a severing or subdividing station wherein the leader of the web is subdivided into a series of successive uniting bands ready to be draped around selected portions of successive groups of rod-shaped tobacco containing and filter material containing sections.
It is also known to employ apparatus of the above outlined character for the making of so-called ventilated filter cigarettes having tubular wrappers which permit cool atmospheric air to penetrate into the column of tobacco smoke flowing from the lighted end of the filter cigarette into a smoker's mouth. The inflowing atmospheric air is to reduce condensate and nicotine contents of tobacco smoke, i.e., to produce a diluting effect upon tobacco smoke.
Heretofore known procedures for the making of ventilated filter cigarettes include the making of perforations in the tubular wrappers of filter cigarettes of unit length or multiple unit length or the utilization of preperforated tipping paper. The tubular wrappers of the filter rod sections and the filter material of such sections must exhibit an adequate permeability to the inflow of air if the ventilated filter cigarettes are to be provided with convoluted uniting bands made of preperforated tipping paper. A drawback of apparatus which produce ventilated filter cigarettes by using off-line perforated tipping paper is that it is not possible to immediately influence the permeability of the wrappers of filter cigarettes if the testing of ventilated cigarettes downstream of the station for the application of uniting bands made of preperforated tipping paper indicates that the actual permeability is insufficient or excessive. The testing can involve a determination of the so-called draw resistance of filter cigarettes or directly the rate of inflow of air into their filter mouthpieces.
Commonly owned U.S. Pat. No. 4,825,883 (granted May 2, 1989 to Hinz et al. for "Method of and machine for making filter cigarettes from pairs of plain cigarettes of double unit length") discloses an apparatus wherein the ventilating unit includes a device for making perforations in the tubular wrappers of filter cigarettes of multiple unit length or in the web of tipping paper upstream of the location where the leader of the wed is subdivided into discrete uniting bands. The details of the device which is to perforate the web of tipping paper are not disclosed; in fact, applicant is not aware of any apparatus capable of making perforations in a running web of tipping paper in a filter cigarette maker or assembler.